A very large number of industrial processes and products are adversely affected when contaminated by microorganisms followed by their subsequent growth. The ubiquitous nature of these microorganisms, which include numerous bacteria, fungi and algae, make prevention of such contamination impractical. However, the practical alternative of including in the product, or of adding to the process, an antimicrobial agent has become very widespread. As used herein, the term "microorganisms" applies to bacteria, fungi, and algae, and mixtures thereof. The mode of action of these compounds, in many cases speculative, appears to vary and includes mechanisms such as interference with the permeability of the cytoplasmic cell membrane, precipitation and/or modification of the cell proteins, and interference with an enzyme system. Regardless of chemical type or of mode of action, it is a practical requirement for an industrial antimicrobial agent that it be effective at very low concentrations, in order that it control the growth of the offending microorganisms without encountering excessive cost or imparting an undesirable property to the process or product, such as creating a health hazard. In practice, a given antimicrobial agent may either destroy all of the contaminating cells present or it may simply prevent their further proliferation to an extent that would be harmful to the substrate or to the system being protected.
The fields of application for industrial anti-microbial agents include cosmetics, disinfectants, wood preservation, manufacture of food and animal feeds, manufacture of paint, especially emulsion paints, cooling water treatment, manufacture of plastics and resins, pulp and paper manufacture, textile manufacture and printing, adhesives, petroleum production and refining, and others. In the petroleum industry, biocides are used to control the growth of bacteria in drilling muds, and to control the bacterial, fungal and algal slimes in industrial recirculating cooling water. They are also added to petroleum products since many of these are stored in tanks under circumstances which permit the accumulation of a layer of water at the bottom of the storage tank. Microbial growth which can take place under these circumstances, probably at the interface, leads to contamination of the fuel with solid matter which can plug mechanical filters. A plugged filter at the point of use can cause shutdown of the burner or engine fed by the fuel. Thus, biocides are added to home heating oil, to diesel fuel and to jet fuel. Petroleum products such as metalworking fluids, which are emulsifiable, are also protected against subsequent degradation by the addition of antimicrobial agents.
A review of the various types of organic compounds that have been found useful as industrial antimicrobial agents, and of their industrial applications, is found in "Encyclopedia of Chemical Technology", Kirk-Othmer, 3rd Edition, Volume 13, John Wiley & Sons, New York, N. Y. pp. 224-251, (1981), the entire content of which is incorporated herein by reference for background purposes.
U.S. Pat. No. 3,833,731 to Grier et al. describes the use of 2-halo-2-halomethyl glutaronitriles as antibacterial and antifungal agents. U.S. Pat. No. 3,877,922 issued to Grier describes the use of the same compounds to control the growth of algae. U.S. Pat. No. 4,462,820 to Grade and Lorenz describe the use of mono- and dibromodicyanomethane as industrial biocides. U.S. Pat. No. 2,802,768 to Meuli discloses an agronomical practice in which fungus infected soil is treated with a haloketone having the formula ##STR1## wherein X is chlorine or bromine and R is an alkyl radical having two to four carbon atoms.